During litigation, parties exchange documents relevant to the litigation. However, some documents may be withheld if they meet certain criteria, such as if the document is covered by the attorney-client privilege or if the document is attorney work product. Documents that are irrelevant to the litigation are also commonly withheld from production. The review and categorization of documents in the course of a litigation is a labor intensive exercise. It would be desirable to simplify the review and categorization of such documents.